1. Field of the Invention
The present invention relates to a data transmission apparatus and a data receiving apparatus. The data transmission apparatus and the data receiving apparatus are connected to each other through a communication line, and a data file recording medium for storing data files which are objects of transmission and reception.
2. Description of the Related Art
Recently, as computer and communication technologies advance, it has been known that a client accesses to a large amount of information stored in a server to retrieve information of interest from a large amount of information. This is done so that the information of interest can be obtained via various types of networks such as a telephone line and a LAN. As recent multimedia technology develops, information as an object of communication is directed to a so-called hypertext including a still picture, a dynamic picture image or animation, sound and the like, in addition to text information, and thus nowadays the size of a data file is increasingly bigger. As a result, there is a need to take more time for the transfer of a data file, and also there is a tendency that an occupation ratio of a communication channel per user, in a communication network is increased. Therefore, there is a fear that the transfer rate will be decreased.
In such a situation, the transfer of a data file is not always successfully completed in accordance with the load conditions of a network. As a result, part of the latter half of the data file is missed due to a time-out during the transfer.
In such a case, an operator makes a fresh start with respect to the transmission of a data file. This causes the load of a network to be more increased. Therefore, it takes more time to complete the transmission of a data file.
On the other hand, from the viewpoint of a data transfer, it is thought that a data file is stored in a storage medium, such as a floppy disk and the like, and such a floppy disk is delivered. However, the data file is not transmitted through the network. In this case, as compared with the case of a transmission through a network, there arises such a problem that a lot of time or labor is required for the delivery of floppy disks or the like. Further, in the event that the data stored in the floppy disks or the like, is missing a part of the data, it will be difficult to promptly take measures. Thus, there is a fear that a user has to wait several days to obtain the data of interest, by means of again delivering the floppy disks or the like.
In view of the foregoing, it is therefore an object of the present invention to provide a data transmission apparatus, a data receiving apparatus and a data file recording medium, which are capable of, even in the event that when a data file is transferred through a communication channel and data loss occurs, minimizing a load of the communication channel and also promptly restoring the missing data.
To achieve the above-mentioned object, according to the present invention, there is a data transmission apparatus in data communication systems having the data transmission apparatus for transmitting data through a communication channel and data receiving apparatuses for receiving data transmitted through the communication channel. The data transmission apparatus and the data receiving apparatuses are connected to each other through the communication channel. The data transmission apparatus comprises:
(1-1) a first file transmission means for transmitting to a data receiving apparatus, a data file including data and information as to the volume of data;
(1-2) a data file generating means for generating, upon receiving notice of the first volume of data received by the data receiving apparatus, which relates to the data file transmitted from the data transmission apparatus, from the data receiving apparatus, or notice of a shortage data volume represented by a difference between the first data volume and the second data volume indicated by data volume information of the data file, a new data file including a shortage data portion, which is not received by the data receiving apparatus, of the data file, and position information included in the data file, said position information being associated with the shortage data portion; and
(1-3) a second file transmission means responsive to the generation of the new data file by the data file generating means for transmitting the new data file generated by said data file generating means to the data receiving apparatus which has issued notices of the first data volume or shortage data volume.
In the above-mentioned data transmission apparatus, it is preferable that said first file transmission means (1-1) transmits the data file including data, information relating to the volume of data, and a program. This program is operated in the data receiving apparatus and adapted to execute a data volume comparison processing in which the first data volume of the received data is evaluated. In addition, the first data volume is compared with the second data volume which indicates the data volume information. A data integration processing in which the received data in the new data file, which is transmitted from the data transmission apparatus in response to notices of the first data volume or the shortage of the data volume issued from the data receiving apparatus is integrated with the received data in the data file received earlier.
In this case, it is preferable that each of the first file transmission means and the second file transmission means transmit a data file including a compression format of data. The first file transmission means transmits the data file including a program operated in the data receiving apparatus and is adapted to execute a data expanding processing in which the received data are expanded, in addition to execution of the data volume comparison processing and the data integration processing.
To obtain the above-mentioned object, the present invention provides a data receiving apparatus in a data communication systems having a data transmission apparatus for transmitting data through a communication channel and a data receiving apparatuses for receiving data transmitted through the communication channel. The data transmission apparatus and the data receiving apparatuses are connected to each other through the communication channel, said data receiving apparatus comprises:
(2-1) a first file receiving means for receiving a data file including data and information as to the volume of data;
(2-2) a data volume comparison means for detecting a first data volume of received data in the data file received by the first file receiving means, and comparing the first data volume with the second data volume indicated by data volume information of the data file;
(2-3) a shortage informing means for informing the transmission apparatus as a transmission source of the data file, in the event that the first data volume is less than the second data volume, of the first data volume or a shortage data volume represented by a difference between the first data volume and the second data volume;
(2-4) a second file receiving means for receiving a new data file including a shortage data portion, which is not received by said first file receiving means, of data in the data file, transmitted from the data transmission apparatus in response to notices of the first data volume or shortage data volume by said shortage informing means, and position information included in the data file, said position information being associated with the shortage data portion; and
(2-5) a data integration means for integrating the received data in the data file received by the said first file receiving means with the received data in the data file received by the said second file receiving means.
In the above-mentioned data receiving apparatus, it is preferable that said first file receiving means (2-1) receives the data file including data, information as to the volume of data, and a program, said program being operated in the data receiving apparatus and adapted to execute a data volume comparison processing in which the first data volume of the received data is evaluated and the first data volume is compared with the second data volume indicated by the data volume information, and a data integration processing in which the received data in the data file received by the said first file receiving means is integrated with the received data in the data file received by the said second file receiving means;
said data volume comparison means (2-2) is implemented by means of executing the data volume comparison processing of the program in the data file received by said first file receiving means; and
said data integration means (2-5) is implemented by means of executing the data integration processing of the program in the data file received by said first file receiving means.
Further, in the above-mentioned data receiving apparatus, it is preferable that each of said first file receiving means (2-1) and said second file receiving means (2-2) receives a data file including a compression format of data; and
said data receiving apparatus further comprises a data expanding means (2-6) for expanding the compression format of data in each of the data files received by said first file receiving means and said second file receiving means.
In this case, it is preferable that said first file receiving means receives the data file including data, information as to the volume of data, and a program, said program being operative in the data receiving apparatus and adapted to execute a data volume comparison processing in which the first data volume of the received data is evaluated and the first data volume is compared with the second data volume indicated by the data volume information, a data integration processing in which the received data in the data file received by the first file receiving means is integrated with the received data in the data file received by the said second file receiving means, and a data expanding processing in which a compression format of data is expanded;
said data volume comparison means (2-2) is implemented by means of executing the data volume comparison processing of the program in the data file received by said first file receiving means;
said data integration means (2-5) is implemented by means of executing the data integration processing of the program in the data file received by said first file receiving means; and
said data expanding means (2-6) is implemented by means of executing the data expanding processing of the program in the data file received by said first file receiving means.
To achieve the above-mentioned object, the present invention provides a data file recording medium for storing data files which are an object of transmission and reception by once in data communication systems having data transmission apparatuses for transmitting data through a communication channel and data receiving apparatuses for receiving data transmitted through the communication channel, said data transmission apparatuses and said data receiving apparatuses are connected to each other through the communication channel, wherein said data file recording medium stores the data file including:
(3-1) data;
(3-2) data volume information of the data; and
(3-3) a program operative in a data receiving apparatus and adapted to execute a data volume comparison processing in which a first data volume of the received data in the data file received by the data receiving apparatus is evaluated and the first data volume is compared with a second data volume indicated by the data volume information, and a data integration processing in which the received data in the data file is integrated with received data in a new data file including a shortage data portion, which is not received by the data receiving apparatus, of data in the data file, transmitted from the data transmission apparatus in response to notices of the first data volume or shortage data volume represented by a difference between the first data volume and the second data volume, issued from the data receiving apparatus to the data transmission apparatus, and position information included in the data file, said position information being associated with the shortage data portion.
In the above-mentioned data file recording medium, it is preferable that at least part of data of the data file stored in said data file recording medium is a compression format of data, and the program of the data file stored in said data file recording medium includes a data expanding processing in which the compression format of data is expanded.